That, my friends, is the kind of thing that was drilled into me at Canadian theology school before I (and shortly thereafter my academic career) went South. It’s a teaching of the late, great Fr. Bernard Lonergan, S.J. (1904 – 1984), and it contains an argument that things can really be known and there really is such a thing as THE truth. (By the mid-20th century, people were casting great doubt on this, and of course today there are ideologies presenting outright lies as “my truth.”)
According to Fr. Lonergan, the way to get to the truth is to examine your own mental processes. It’s not navel gazing as much as stepping outside of your brain, for a moment, and asking yourself what you are experiencing, and what you think it is, and if you might be wrong about that. It’s an incredibly useful exercise if you are prone to catastrophizing–as I currently am.
Here is a sadly common train of thought for your poor cooped up correspondent: